Ellipsograph



2 SheetsSheet 1.

(No Model.)

J. HOTTINGER.

BLLIPSOGRAPH.

Elm 532,155.

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(No Model.) 2 Sheets-Sheet 2,

r, J. HOTTINGER.

' ELLIPSOGRAPH.

.No. 532,155. Patented Jan. 8, 1895.

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NrTED STATES JOHN HOTTINGER, OF ST. LOUIS, MISSOURI.

ELLI PSOG'RAPH.

SPECIFICATION formingpart of Letters Patent No. 532,155, dated January 8, 1895.

Application filed July 12, 1894.

To all whom it may concern:

Be it known that I, JOHN HOTTINGER, of the city of St. Louis, State of Missouri, have invented certain new and useful Improvements in Ellipsographs, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof.

My invention has relation to improvements in ellipsographs and consists in the novel arrangement and combination of parts more fully set forth in the specification and pointed out in the claims.

In the drawings, Figure l is a plan view of the instrument after the marker arm has described a quarter of a revolution. Fig. 2 isa middle vertical section of the same with the marker arm however in its original position or that indicated in Fig. 3. Fig. 3 is a plan view of the instrument with marker arm in its normal position and with the index secured to said arm shifted from its central position a few points along the eccentric scale. Fig. 4 is a bottom plan view of the washerindex. Fig. 5 is an elevation of the same. Fig. 6 is a detail plan view of the adjustable arm to which the index and the remaining parts arev secured, and Fig. 7 is an elevation of the same.

The object of my invention is to construct an ellipsograph which will be simple, accurate, readily assembled, and one which shall be light and durable.

To this end I have devised an instrument which in detail can be described as follows:

Referring to the drawings, 1 is a frame of suitable design or outline having two opposite turned up edges 2, forming parallel grooves 3 within which is confined and loosely adapted to revolve the generating circle 4. Extending from the center of each of the edges 2 on the frame 1 is *a slot 5 of suitable width the purpose of which is hereinafter to be described. The normal position of the generating circle is that shown in Fig. 3, that is, the radial slot 6 thereof is superposed over the slot 5 of the frame. The slots 5 and 6 are of unequal width, the former being the wider to accommodate certain parts as more fully to be described. Along one side of the slot 6 of the generating circle is the eccentric scale 7 by which the Serial No. 517.332. (Ilo model.)

eccentricities of the ellipses to be described. are determined. lVhen the parts are in their normal position the slots 5 and 6 are respectively adapted to receive the enlarged circular head 80f an arm 9, and its upper rectangular reduced portion or offset 10. The circular head and offset 10 are thus shown simultaneously inserted. into the slots 5 and 6 in Figs.

2 and 3, the head snugly fitting the slot 5 of the frame, and the offset 10 accurately fitting the slot 6 of the generating circle. From the ofiset 10 there extends a screw-threaded projection 11 over which is adapted to loosely pass a washer 12 of sufficient diameter to overlap the meeting edges of the offset 10 and the slot 6. The washer has a projecting pin 13 on its under surface adapted to pass into a suitable depression 14 on the surface of the offset, the objectof this arrangement being to always keep the washer in one position with respect to the remaining parts. A thumb nut 15 finally secures the washer and binds thearm 9 and the generating circle firmly together, allowing the arm however to turn and slide within the slot 5 of the frame. The washer is provided with a notch whose short edge 16 serves as an index for the eccentric scale 7 on the circle.

The lower end of the right angular arm 9 carries a fork 17 within which is clamped or secured by a thumb or binding screw 18 a movable tube 19. This tube carries an extensiblo marker arm 20 clamped within the tube bya binding screw 21, the free end of the marker arm carrying a clamp 22 within which is adapted to be secured a pencil 23 or other suitable device. It is to be observed that the connection between the center of rotation (that is the projection 11) and the tube 19 and its arm 20 need not be a right angular arm 9, for the said connection may be a straight arm, but the former is preferable since when the tube 19 and arm 20 are pushed fully toward the arm 9, the pencil point comes directly under the center of the projection 11, this marking the center of the ellipse. From the middle of each side 2 of the frame projects outwardly the tubular extension 24 accommodating the extensible bars 25 at the free end of each of which is the leg 26, each leg carrying at the middle of the too ' will describe a circle.

bottom thereof a pointer 27 (see Fig. 2), the pointers being in line with the continuation of the axis of the ellipse described by the instrument, and hence serving to determine the direction of the major axis of the ellipse to be described. Both the legs being outwardly extensible as well as the marker arm it is apparent that ellipses of variable lengths may be described with this instrument.

It is apparent that if the arm 9 with its index is shifted to the zero mark on the eccentrio scale, and the parts then firmly set or secured, this being of course the center of the generating circle, then if the circle be turned about its center within its confines or grooves 3, the pencil at the end of the marker arm If however the arm 9 with its index and other parts secured thereto is shifted any number of points from zero along the eccentric scale, and the parts then set as seen in Fig. 3, and the generating circle is turned, the marker arm will turn with it,but instead of describing a circle, the center of rotation-being the center of the screw-threaded projection 11 about which the arm rotateswill shift from its original position along the slot 5 as indicated by dotted lines in Fig. 3, thus describing an ellipse, the minor axis thereof being equal to twice the distance from the screw-threaded projection 11 fixed to the generating circle to the pencil point (that is, the horizontal distance) and the major axis being equal to this distance plus the distance that the center of rotation has shifted or traveled along the slot 5 during one complete revolution of the generating circle, the amount shifted being of course equal to twice the distance that the index was originally set from the center or zero point along the scale. It is apparent too that the end of the marker opposite to that which carries the pencil would describe an ellipse at right angles to the main ellipse, the long axis of this second ellipse being twice the distance from the center of rotation to that end of the arm, and the short or minor axis being this distance minus twice the distance the index had been originally shifted from the zero point along the eccentric scale.

The successive positions of the generating circle and its attachments are variously indicated in the several figures.

It is of course within the spirit of my invention to reverse the general relation between the frame and the generating circle, it being possible of course to have the circle stationary and have the frame revolve instead.

Having described my invention, what I claim is 1. An ellipsograph comprising a frame, grooves forming a part of the same, a slot formed in said frame between the grooves, a generating circle mounted on said frame adapted to revolve within the grooves, a radial slot carried by the circle, a marker arm, means for securing the marker arm to the circle in any position along the radial slot, and means for shifting the center of rotation of the marker arm along the slot of the frame during the revolution of the generating circle, substantially as set forth.

2. An ellipsograph comprising a frame, grooves forming part of the same, a slot formed in said frame between the grooves, a generating circle mounted on said frame and adapted to revolve within the grooves, a radial slot carried by the circle, an eccentric scale adjacent to the radial slot, a marker arm carrying an index co-operating with the scale, means for securing the marker arm to the circle in any position along the scale, and means for shifting the center of rotation of the marker arm along the slot of the frame during the revolution of the generating circle, substantially as set forth.

3. In an ellipsograph, a suitable slotted I frame, a generating circle mounted on and adapted to revolve on said frame, a radial slot on said circle adapted to be superposed over the slot of the frame, an arm having a rounded head adapted to fit in the slot of the frame, an angular offset adapted to engage with the slot on the circle, a screw-threaded projection extending from said offset, a suitable index carried by the projection, means for securing the index and the several parts together, and a scale on the circle co-operat-' ing with the index, substantially as set forth. 4. In an ellipsograph, a suitable revolving arm, an offset carried by the upper end of the same, a screw-threaded projection extending from the outer surface of the offset, a suitable depression in said surface, a washer adapted to pass over the projection, a peg on the un der surface of the washer adapted to enter the depression in the off-set, a notch on said washer serving as an index, and a thumb nut for securing the parts, substantially as set forth.

In testimony whereof I affix my signature in the presence of two witnesses.

JOHN HOTTINGER.

Witnesses:

JAMES J. ODoNoHoE, EMIL STAREK.

IIO 

